Risk factors for PICU mortality
Overall PICU mortality for all admissions was 46.2% (24/52). There were
no significant difference between survivors and nonsurvivors with
respect to age, sex, EBV infection, Pediatric Risk of Mortality III
(PRISM III) score at PICU admission, and the type of SHLH. For all
patients, the factors that were significantly different between
survivors and nonsurvivors were the length of PICU stay, number of organ
dysfunction, mechanical ventilation, and vasoactive agents needed.
Table 1 lists data comparing laboratory variables for survivors versus
non-survivors. TBIL, DBIL, ALT,
AST, ALB, PT, FIB, BUN and CR, as well as WBC, HB, PLT level at CRRT
initiation were no different for survivors compared to non-survivors. In
contrast, non-survivors had significantly higher levels of
serum LDH (1404.5 (713.25, 2793) vs.
982.7 (692, 1461) (U/L), P = 0.037), LAC(1.9 (1.3, 4.53) (mmol/L) vs.
1.65 (0.8, 2.45) , P=0.034 ), triglyceride (2.88 (1.94, 5.08) (mmol/L)
vs. 2.41 (1.63, 3.32), P=0.032) at CRRT initiation.
In addition, patients with SHLH and MODS who died during their hospital
displayed a significantly higher IL-6 (28.66 (17.77, 113.63) (pg/ml)
vs.0.98 (0.1, 4.63) P=0.000) at CRRT initiation when compared to those
who survived. No difference was observed in serum IL-1, IL-10, TNF-a,
SCD25, IL-8, IL-12 and IL-18 between patients discharged alive from PICU
and those who died during PICU stay.
Logistic regression analysis using PICU mortality as the endpoint was
performed on categorical and continuous variables. Regression modeling
identified two independent risk factors of mortality: the number of
Organ dysfunction (OR: 3.464; 95% CI [1.018-11.788], P=0.047), and
the serum IL-6 level (OR:1.388; 95% CI [1.058-1.821], P= 0.018).
Receiver Operating Characteristic (ROC) curve was used to evaluate the
power of the two independent variables. The number of Organ dysfunction
and the serum IL-6 level at PICU admission were found high
discriminative power with AUC values respectively of 0.896 (SE 0.046,
95% CI 0.806-0.986) and 0.964 (SE 0.026, 95% CI 0.913-1.00) (Table 2).
Furthermore, we used the highest Youden Index to determine the most
discriminative cut-off point for the number of Organ dysfunction and the
serum IL-6 level at PICU admission to predict PICU mortality (Table 3-4,
Figure 1). A value of serum IL-6 level of 13.12pg/ml and the number of
Organ dysfunction of 3 at CRRT initiation have been identified as
cut-off points.